Low verbal ability predicts later violence in adolescent boys with serious conduct problems.

Background: Delinquent adolescents are a known high-risk group for later criminality. Cognitive deficits correlate with adult criminality, and specific cognitive deficits might predict later criminality in the high-risk adolescents.
Aims: This study aimed to explore the neuropsychological performance and predictors of adult criminal offending in adolescents with severe behavioural problems.
Methods: Fifty-three adolescents (33 boys and 20 girls), aged 15-18 years, residing in a reform school due to serious conduct problems, were examined for neuropsychological profile and psychiatric symptoms. Results were compared with a same-age general population control sample, and used for predicting criminality 5 years after the baseline testing.
Results: The reform school adolescents' neuropsychological performance was weak on many tasks, and especially on the verbal domain. Five years after the baseline testing, half of the reform school adolescents had obtained a criminal record. Males were overrepresented in both any criminality (75% vs. 10%) and in violent crime (50% vs. 5%). When cognitive variables, psychiatric symptoms and background factors were used as predictors for later offending, low verbal intellectual ability turned out to be the most significant predictor of a criminal record and especially a record of violent crime.
Conclusions: Neurocognitive deficits, especially in the verbal and attention domains, are common among delinquent adolescents. Among males, verbal deficits are the best predictors for later criminal offending and violence.
Clinical Implications: Assessing verbal abilities among adolescent population with conduct problems might prove useful as a screening method for inclusion in specific therapies for aggression management.